Infrared telescopes need to be very cold (often below 10 K) to be effective. So do a few other miscellaneous things, including superconductors, if we ever use them in space for e.g. mass drivers or radiation shielding. When it's launched, JWST will have a 500W-550W four-stage cooling system that manages to reject a measly 76mW at 6.2 K — roughly a 7000 to 1 input power to useful cooling load ratio. However, the Zeeman slower seems tailor-made for this, since it cools only with radiated heat, can cool down to the required temperature range, and is already sometimes used instead of that same basic refrigeration design (Joule-Thomson etc) in Earth-bound labs, where there's convection and conduction to dump the extra heat more efficiently than via radiation alone. Given this, are there any obstacles to Zeeman slowers being seriously considered for cold-instrument mission design in the near future?
(This is a more focused version of a similar question I recently asked, about general systems cooling.)